1. Field of the Invention
The present invention relates generally to plant molecular biology and genetic engineering and more specifically to the production of genetically modified seed plants from which enlarged or diminished seeds or fruits can be obtained.
2. Background Information
Seed and fruit production are multi-billion dollar commercial industries and primary sources of income for numerous states in the United States and for many countries around the world. Commercially valuable seeds include, for example, rapeseeds, cottonseeds and sunflower seeds, which are prized for the vegetable oil that can be pressed from the seed. The seeds of leguminous plants such as peas, beans and lentils also are commercially valuable as they are rich in proteins, with soybeans, for example, consisting of 40-45% protein and 18% fats and oils. In addition, coffee is a valuable crop made from the dried and roasted seeds of Coffea arabica plants, while chocolate is made from the cacao seed or xe2x80x9cbean.xe2x80x9d Similarly, many fruits are commercially valuable, including, for example, corn, rice, wheat, barley and other cereals, nuts, legumes, tomatoes, and citrus fruits.
Unfortunately, seed and fruit production are both limited inherently, for example, due to the availability of suitable growing seasons and growing conditions, including the finite resource of arable land. In addition, seed and fruit production are limited by the yield obtained from a plant, which is a function, in part, of the average size of the seeds and fruits produced. As a consequence, methods for increasing seed or fruit production from a seed plant would help in combating the increased need for food, particularly as the world population continues to expand. Thus, a need exists for developing methods to increase the yield of seeds and fruits from cultivated plants. The present invention satisfies this need and provides related advantages as well.
The present invention provides a non-naturally occurring seed plant that is characterized by producing seeds of increased size due to ectopic expression of a nucleic acid molecule encoding an AGL8-related gene product. The AGL8-related gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog such as Arabidopsis AGL8 (SEQ ID NO:2).
In one embodiment, the invention provides a transgenic seed plant characterized by producing seeds of increased size due to ectopic expression of an exogenous nucleic acid molecule encoding an AGL8-related gene product. The nucleic acid molecule encoding the AGL8-related gene product can be operatively linked to an exogenous regulatory element such as a constitutive reguIatory element or seed-selective regulatory element. The invention additionally provides a tissue, such as a seed, which is derived from a non-naturally occurring seed plant of the invention.
The invention further provides a method of producing a non-naturally occurring seed plant characterized by producing seeds of increased size. The method is practiced by ectopically expressing a nucleic acid molecule encoding an AGL8-related gene product in the seed plant, whereby seed size is increased due to ectopic expression of the nucleic acid molecule. In one embodiment, the method is practiced by introducing an exogenous nucleic acid molecule encoding an AGL8-related gene product into the seed plant.
Kits for generating a transgenic seed plant characterized by producing seeds of increased size also are provided herein. The kits of the invention include a nucleic acid molecule encoding an AGL8-related gene product and a seed-selective regulatory element. In a kit of the invention, the AGL8-related gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog. If desired, a kit for generating a transgenic seed plant characterized by producing seeds of increased size can include a plant expression vector containing a nucleic acid molecule encoding an AGL8-related gene product operatively linked to a seed-selective regulatory element.
The invention additionally provides a non-naturally occurring seed plant that is characterized by producing seeds of decreased size due to suppression of AGL8-related gene product expression. The AGL8-related gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog. In one embodiment, expression of the AGL8-related gene product is selectively suppressed in seed tissue. In addition, the invention provides a tissue, such as a seed, which is derived from a non-naturally occurring seed plant characterized by producing seeds of decreased size due to suppression of AGL8-related gene product expression.
Further provided herein is a non-naturally occurring seed plant that is characterized by producing fruit of increased size due to ectopic expression of a nucleic acid molecule encoding an AGL8-family gene product. The AGL8-family gene product can have substantially the amino acid sequence of an AGL8 ortholog, for example, the amino acid sequence of Arabidopsis AGL8 (SEQ ID NO:2).
In a related embodiment, the invention provides a transgenic seed plant that is characterized by producing fruit of increased size due to ectopic expression of an exogenous nucleic acid molecule encoding an AGL8-family gene product. The exogenous ectopically expressed nucleic acid molecule encoding an AGL8-family gene product can be operatively linked to an exogenous regulatory element, which can be, for example, a constitutive regulatory element or a valve-selective regulatory element.
A tissue derived from a non-naturally occurring seed plant that is characterized by producing fruit of increased size due to ectopic expression of a nucleic acid molecule encoding an AGL8-family gene product also is provided herein. The invention provides, for example, a fruit derived from a non-naturally occurring seed plant of the invention.
The invention also provides a method of generating a.non-naturally occurring seed plant that is characterized by producing fruit of increased size. The method includes the step of ectopically expressing a nucleic acid molecule encoding an AGL8-family gene product in the seed plant, whereby fruit size is increased due to ectopic expression of the nucleic acid molecule. In one embodiment, the method includes the step of introducing an exogenous nucleic acid molecule encoding an AGL8-family gene product into the seed plant.
Further provided by the invention are kits for generating a transgenic seed plant characterized by producing fruit of increased size. The kits include a nucleic acid molecule encoding an AGL8-family gene product as well as a valve-selective regulatory element. The AGL8-family gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog. If desired, a kit of the invention can include a plant expression vector containing a nucleic acid molecule encoding an AGL8-family gene product operatively linked to a valve-selective regulatory element.
The invention further provides a non-naturally occurring seed plant that is characterized by producing fruit of decreased size, in which expression of an AGL8-family gene product is suppressed. In such a non-naturally occurring seed plant of the invention, an AGL8-family gene product can have, for example, substantially the amino acid sequence of an AGL8 ortholog. In one embodiment, expression of the AGL8-family gene product is selectively suppressed in valve tissue. Also provided herein is a tissue, such as a fruit, derived from a non-naturally occurring seed plant that is characterized by producing fruit of decreased size, in which expression of an AGL8-family gene product is suppressed.